Intellij can not locate some classes - Play SBT. Intellij bug? - intellij-idea

I have a few import statements in my project that are displayed in RED. Intellij shows 'Cannot resolve symbol' errors, and I am not able to autocomplete these classes or their methods. However, when I run my project it runs perfectly fine. This is strange so much so, that lets say I have an import statement
import org.apache.velocity.app.Velocity
It cannot resolve the 'Velocity' class, even though when I do a ctrl+b selecting the 'app' package, it clearly shows the Velocity class:
I am lost in this and I am struggling to code like this. Any help will be appreciated.
Best Regards.
EDIT: In my project, some of the dependencies are also not resolved, although I refreshed my project multiple times. The exact same dependencies are resolved in my colleague's system, who is using the same code-branch and environment as me.
I can see that the unresolved dependencies lie inside the play.sbt package, but are still not resolved. Is there a compatibility issue between Intellij("15.0.2") and SBT("0.13.8" mentioned in build.properties of my app)?

Reimport project using option 'Import project from external model' and choose 'sbt'. In next window choose options like 'use auto-import' and download 'sources for SBT and plugins'.

Related

where is com.intellij.rt.junit.junitstarter

i use intellij with junit to run tests (new), when i debug my test code for practice, one of the very first lines of code that seems to run is some method called main from package called com.intellij.rt.junit. I've tried clicking on it as well as searching for it open that package or class to see what's inside but i can't find it all. anyone know what it is or where i could find it in intellij and why i can't just access it from the debugger like every other class? i have junit 5.8 installed in maven.
y.bedrov's analysis is quite right.
com.intellij.rt.junit.JUnitStarter is part of IDE. In your case, the IDE is IntelliJ IDEA. You may find the source code in this local path:
/Applications/IntelliJ IDEA.app/Contents/plugins/junit/lib/junit-rt.jar
then import the jar package into your own project to read the source code conveniently.

Coroutines working but IntelliJ shows errors

I am working on a project using kotlinjs for nodejs and I start to learn coroutines and integrate them into my code to say goodbye to the callback hell.
I managed to get coroutines working, my code can be compiled and executed, everything seems fine.
...except: The IDE still shows me errors. It seems to be confused by the additional libraries I added in order to get coroutines running.
I am currently fiddling around with the library dependencies, sometimes some errors go away, but then some code gets red which was okay before...
This is what I see:
Case 1:
Cannot access class 'kotlinx.coroutines.experimental.CoroutineContext'. Check your module classpath for missing or conflicting dependencies
Case 2:
Unresolved reference: JsModule
Modifier 'external' is not applicable to 'class'
You see, launch is recognized when I add the stdlib, but then the IDE complains with the other two errors.
Again, please note: In both cases, actual compilation is successful!
I am using IntelliJ 2018.1 with Kotlin Plugin 1.2.41.
Thanks to Alexander Chernikov at youtrack.jetbrains I could resolve my problem.
I cite his explanation:
The issue is that JavaScript libraries should be marked with special attribute to be recognized.
When they are imported from pom.xml or build.gradle, this mark is set, so the feature works.
In your project they are not marked.
At the moment, to correct the libs manually, please open .idea/libraries/org_jetbrains_kotlin_kotlin_stdlib_js_1_2_41.xml and .idea/libraries/org_jetbrains_kotlinx_kotlinx_coroutines_core_js_0_22_5.xml.
In both files find type="repository" and replace it with type="kotlin.js".
Make sure IDEA sees the change. (You can exit IDEA, make the change and restart.)
Then you can keep only these two libs in dependencies. The editor should work.
Here is the issue link:
https://youtrack.jetbrains.com/issue/KT-24575
There I have also attached a sample project with the problem.

Is there any way to reuse IntelliJ ui components such as com.intellij.ui.components.JBScrollPane?

When calling new JScrollPane, I was prompted to use a JBScrollPane.
com.intellij.ui.components.JBScrollPane
But when I do import com.intellij.ui.components.JBScrollPane, the compilation triggered an error.
error: cannot find symbol
import com.intellij.ui.components.JBScrollPane;
I tried adding this repository artifact, but it doesn't work.
This inspection is supposed to be shown only in the code of IntelliJ itself and IntelliJ plugins; if you saw it in a regular Swing project, it's a bug.
IntelliJ components can be adapted to be used outside of IntelliJ, but they are not packaged and published in a way that makes it easy.

Using the import statement. Which files is it importing from?

I'm trying to migrate my eclipse install from one workstation to another. I primarily work with Selenium, so I've copied my workspaces, imported the projects and imported the appropriate jars. However, I am still getting a lot of errors including some stating the import statements are failing to find certain packages.
Half of the errors cleared when I finished importing the last of the jars, but it seems like it's missing something. Basically guessing at this point, I right clicked my project and hit "build project", which cleared the import errors, but the rest of my code has errors indicating things are not imported correctly. I have a feeling the build path is still not configured correctly. Is there a way I can look at my old PC and see what files the import statement is looking for?
When you copied the files to another machine, and imported the project, some jars were not properly added to the classpath. So the compiler complained about not being able to find a class/package in an import statement. You can definitely have a look at the old work station, and look at the project imported jars. You can find those by:
Right click on the project in "Project Explorer", and select "Build Path > Configure Build Path".
This will give you an idea about what you are missing.
Alternatively, (if the libraries you are missing are third party), you can google the missing import statement, and get a clue in which jar (library) contains the jar, then download and add it to the classpath of the project.

Cannot resolve symbol after importing GitHub Project to IntelliJ

So I'm working on a project that my friend had started. However, for some reason, after importing it from GitHub for the first time, there are hundreds of errors everywhere. It's a MineCraft plugin, and things such as 'Listener', 'EventHandler', '.getPlayer', are all getting 'Cannot resolve symbol'.
I took some screenshots, not sure if they will help in resolving any of this:
https://i.gyazo.com/81c21c5da19d6be1235870a4e213056d.png
https://gyazo.com/c692a04e3d598fe20de0ad79000cc409
Based on your screenshots, the project is referencing jars that IntelliJ can't find. In the project structure dialog, click on "problems" at the bottom and you should get a list of issues. Depending on the type of project you might need manually download the libraries.